NEW YORK (AP) — Stocks edged lower on Wall Street at the start of a big week for company earnings.About a third of the companies in the S&P 500, including Exxon Mobil and Apple, are reporting earnings this week. Analysts currently expect earnings to rise by 2 percent in the first quarter, down from the 7.7 percent increase in the fourth quarter, according to S&P Capital IQ.The Dow Jo